1. Department of Materials ScienceState Key Laboratory of ASIC and SystemsFudan University Shanghai 200433 P. R. China
2. Department of Materials Science and EngineeringFrederick Seitz Materials Research LaboratoryUniversity of Illinois at Urbana‐Champaign Urbana IL 61801 USA
3. Center for Bio‐Integrated ElectronicsNorthwestern University Evanston IL 60208 USA
4. School of MicroelectronicsState Key Laboratory of ASIC and SystemFudan University Shanghai 200433 P. R. China
5. Material Systems for NanoelectronicsChemnitz University of Technology Chemnitz 09107 Germany
6. Department of PhysicsYonsei University Seoul 03722 Republic of Korea